Global increase in record-breaking monthly-mean temperatures

by

Dim Coumou, Alexander Robinson, Stefan Rahmstorf

,

Climatic Change

Analyzes 131-years (1880–2010) of climate data and finds that the number of local record-breaking monthly temperature extremes is now on average five times larger than expected in a climate with no long-term warming

Finds that continental regions with an exceptionally large number of 131-year records in the last decade (2001–2010) are primarily located in the tropics and include East Africa, India and Amazonia

Finds that, globally, the probability that the records set in between 2001-2010 due to the long-term warming rather than stationary variability is more than 80%; an alternative way of saying this is, on average there is an 80 % chance that a new monthly heat record is due to climatic change

Identifies notable exceptions, including: the eastern U.S., Australia, Southeast Asia and Argentina, where probabilities range from about 10 to 50 % depending on the specific location

States that large regional differences exist in the number of observed records

Finds summertime records, which are associated with prolonged heat waves, increased by more than a factor of ten in some continental regions including parts of Europe, Africa, southern Asia and Amazonia

Finds that the observed records cluster both in space and in time

Finds that strong El Niño years see additional records superimposed on the expected long-term rise

Predicts that under a medium global warming scenario, by the 2040s the number of monthly heat records globally to be more than 12 times as high as in a climate with no long-term warming